The elephant in the diversity room

Although there’s a lot of heated discussion around diversity, I feel many of us ignore the elephant in the web development diversity room. We tend to forget about users of older or non-standard devices and browsers, instead focusing on people with modern browsers, which nowadays means the latest versions of Chrome and Safari.
This is nothing new — see “works only in IE” ten years ago, or “works only in Chrome” right now — but as long as we’re addressing other diversity issues in web development we should address this one as well.
Ignoring users of older browsers springs from the same causes as ignoring women, or non-whites, or any other disadvantaged group. Average web developer does not know any non-whites, so he ignores them. Average web developer doesn’t know any people with older devices, so he ignores them. Not ignoring them would be more work, and we’re on a tight deadline with a tight budget, the boss didn’t say we have to pay attention to them, etc. etc. The usual excuses.
Besides, let’s be realistic, shall we? The next billion, most of whom are on cheap Android devices without the latest and greatest browsing software, are mostly poor — and mostly black or brown anyway — so they don’t fit in our business model. We only cater to whites — not because we’re racist (of COURSE we aren’t!) but because of … well, the Others are not our market.
So far, this diversity problem plays out the same as the others. However, there’s one important difference: while other diversity problems in web development could conceivably be solved by non-web developers (by managers, for instance), the old-devices problem can only be solved by us because we’re the only ones who know how to do it.
Besides, taking care of all users is our job. So let’s do our job, shall we?
And let’s start at the start. Let’s admit we have a prejudice against users of old or non-standard devices and browsers, just as we have a prejudice against women and non-whites, and for exactly the same reasons.